Spin-on filter including improved seal arrangement and methods

ABSTRACT

A fluid filter assembly includes a housing having a closed end and an open end; a filter element operably oriented in the housing; a baffle plate mounted to operably cover the housing open end; the baffle plate including a first axial face and an outer circumferential wall circumbscribing the first axial face; the outer circumferential wall being groove-free; the first axial face defining at least a first sealing groove; and a sealing gasket oriented in the first sealing groove; the sealing gasket forming a seal between the housing and the baffle plate. Methods of constructing, installing, and servicing includes fluids filters of the type described.

This application is a divisional application of application Ser. No.10/132,982, filed Apr. 26, 2002, now U.S. Pat. No. 6,823,996.Application Ser. No. 10/132,982 is incorporated by reference herein.

TECHNICAL FIELDS

This disclosure concerns generally a fluid filter. In particular, thisdisclosure relates to a filter incorporating an improved sealarrangement.

BACKGROUND

Filters have been employed in a variety of applications includinghydraulic systems and engine lubrication systems. Such filter assembliesgenerally include a cylindrical filter element within a can or housingwith a baffle or attachment plate at one end to connect the filter to afilter head, typically by a threaded joint. A central opening andseveral surrounding openings in the baffle direct flow through thefilter and, in particular, the filter element. The flow can be in eitheran inside-out (forward flow) or an outside-in (reverse flow) pattern. Acircular gasket serves as a seal between the baffle and the can orhousing.

Various models and designs of filters have been known over the years.Each design improves on an aspect of these filters. Continuedimprovement in filters are desired.

SUMMARY OF THE DISCLOSURE

In one aspect, a fluid filter assembly is provided. The fluid filterassembly includes a housing having a closed end and an open end; afilter element operably oriented in the housing; a baffle plate mountedto operably cover the housing open end; the baffle plate including afirst axial face defining at least a first sealing groove; and a sealinggasket oriented in the first sealing groove; the sealing gasket forminga seal between the housing and the baffle plate.

In other aspects, methods of constructing, installing, and servicingincludes fluids filters of the type described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a filter assembly secured to a filterhead, constructed according to principles of this disclosure;

FIG. 2 is a cross-sectional view of the filter assembly taken along theline 2—2 of FIG. 1, the filter assembly including a filter elementoriented within a can or housing;

FIG. 3 is an enlarged view of a portion of the cross-sectional viewdepicted in FIG. 2;

FIG. 4 is a perspective view of the baffle plate utilized in the filterassembly of FIGS. 1-3;

FIG. 5 is a side elevational view of a system incorporating the filterassembly of FIGS. 1-3; and

FIG. 6 is an enlarged cross-sectional view of a section of a prior artfilter assembly.

DETAILED DESCRIPTION A. Overall Assembly; Systems of Use

Referring first to FIG. 1, there is illustrated a fluid filter assembly10. Filter assembly 10 is particularly adapted for filtration of liquid,for example oil, as for example in a hydrostatic transmission or otherhydraulic system. The filter assembly 10 includes a filter cartridge orelement 12 (FIG. 2) operably oriented in a can or housing 14. The filterassembly 10 is operably mounted to a filter block or filter head 16,typically by screwing the filter assembly 10 onto the filter head 16 byinternal threads on the filter assembly 10.

The filter assembly 10 is utilized in a filtering system 18. Thefiltering system 18 includes a supply 20 for supplying dirty fluid tothe filter assembly 10 through an inlet 22 of the filter head 16. Thefluid enters and is filtered or cleaned by the filter element 12. Thecleaned fluid exits the filter head 16 at an outlet 24 and is carriedaway by pipe 26.

In reference now to FIG. 5, one application for the filter assembly 10is to remove particulate matter from hydraulic fluid that is used in avehicle 28. In FIG. 5, the vehicle 28 depicted is a tractor 30. Anexample of a tractor is an agricultural tractor that has a hydrostatictransmission and a hydraulic system, both of which require a filter. Thehydraulic system can be used for a variety of purposes including raisingand lowering farm implements such as plows. A hydraulic system can alsobe used to raise and lower earth moving equipment such as blades,buckets, backhoes, and scrapers. Other applications for the filterassembly 10 include other farm equipment, construction equipment,skidders, loaders, off-road vehicles, over-the-highway trucks,automobiles, industrial machines, and other devices that require thefiltering of fluids. Additionally, the filter assembly 10 can be used toremove foreign matter from a variety of different fluids. Examples ofliquid fluids include other hydraulic fluids, engine lubrication oil,diesel fuel, gasoline, engine coolant, automatic transmission fluid andothers.

B. Some Problems With Existing Filter Assemblies, FIG. 6

Attention is next directed to FIG. 6 which depicts a portion of a priorart filter assembly 200. In the filter assembly 200, there is a filterelement 202 held within an outer can or housing 204. The filter element202 includes filter media 206 potted within an end cap 208. The end cap208 includes an opening 210, which circumscribes a portion of a baffleplate 212. The baffle plate 212 is secured across an open end of thehousing 204. The baffle plate 212 has an edge 214 that provides amechanical interlock between the baffle plate 212 and the housing 204.The edge 214 forms the outer circumferential surface and outer peripheryof the baffle plate 212. As such, the edge 214 is an outer annularsurface. The edge 214 includes a groove 216 that holds a sealing gasket218 therein to form a seal 220 between the baffle plate 212 and thehousing 204. The housing 204 includes a fold 222 that engages a top,exterior surface 224 of the baffle plate 212 to help securely lock thebaffle plate 212 and the housing 204 together.

The prior art filter assembly 200 can introduce certain problems. Forexample, the baffle plate 212 is die cast. The casting is then threadedto form threads 226 on an inside diameter 228 of the baffle plate 212.The outside diameter along edge 214 is machined to clean up the castinggates and overflows and the seal groove 216 is machined into thecircumference.

Due to the depth of the groove 216 and the location of the groove 216along the edge perimeter 214, the baffle plate 212 should be vacuumimpregnated with a material, such as Loctite, to seal any porosity inthe casting that has been exposed by the machining operation. Thesealing gasket 218, usually a lathe-cut sealing gasket, is then placedinto the groove 216. This gasket 218 has double chamfers and lubricationso that the baffle plate 212 can be pressed into the open end of thehousing 204. Insufficient lubrication can cause the sealing gasket 218to roll, or otherwise not be installed properly and result in adefective product.

After the sealing gasket 218 is installed and the element 202 is placedon the baffle plate 212, the entire assembly (element 202 and baffleplate 212) is pressed into the housing 204 and the filter is seamedusing a single fold seam method to form fold 222. After painting (ifdesired), a molded O-ring face seal 230 is inserted into a face sealgroove 232 on the top exterior surface 224 of the baffle plate 212.

C. Improved Filter Assembly 10, FIGS. 1-5

The filter assembly 10 of FIGS. 1-5 was designed to address problems ofthe prior art filter assembly 200. For example, it was recognized thatif the sealing groove 216 were moved from the circumferential edge 214to the top exterior surface 224 (the face) then the sealing gasket willbe located in a groove that is cast into the face of the baffle plateinstead of machined into the perimeter of it. As a result, machiningtime is reduced, the porosity that is exposed is negligible, and therequirement for impregnation of material (such as Loctite) iseliminated. In addition, in the filter assembly 10 of FIGS. 1-5, thesealing gasket does not need to have double chamfers, which results incost savings. Further, when manufacturing new filter assembly 10, thesealing gasket is compressed by the seaming operation and does not haveto be pressed into the housing. In the prior art filter assembly 200,pressing the baffle plate 212 with the sealing gasket 218 into theradial edge 214 requires a significant mount of force, and the sealinggasket 218 could roll, causing scrap and rework. Details of the improvedfilter assembly 10 are discussed below.

In reference now to FIG. 2, the filter assembly 10 includes the filterelement 12 operably oriented within the housing 14. The filter housing14 has an interior volume 32 designed to accept the filter element 12therein. The filter housing 14 generally has an open first end 34 and aclosed second end 36. Preferably, the housing 14 is of generallythin-walled construction having sufficient rigidity to withstand thepressure experienced during typical filtering operations. Housing 14 istypically metal, plastic, or other suitable metal; if housing 14 ismetal, it is typically formed by stamping or drawing from the metal.

The filter element 12 is located inside the interior volume 32. Thefilter element 12 includes a filtering material 38 for removingcontaminants, such as particulate, from the fluid being filtered.Filtering material 38 extends from, and is potted within, a first endcap 40 and a second end cap 42. Filtering material 38 defines an openinterior volume 44. Typically, the filtering material 38 is materialsuch as cellulous, paper, non-woven material, synthetic material, andthe like. The filter material 38 may be treated or coated to improve itsfiltering capabilities.

In the one shown, the filter material 38 includes filter media 46 thatis generally a pleated, porous material, such as paper. A perforatedtubular inner liner 48 can be included in the filter element 12. Theinner liner 48 is surrounded by an extension of the filter media 46 andtypically extends between the first and second end caps 40, 42.

The first end cap 40 is an open end cap and includes an opening 50therein. The opening 50 receives, circumscribes, and surrounds a portionof a baffle plate 52. The baffle plate 52 is secured across the open end34 of the housing 14. The second end cap 42 is a closed end cap thatextends across and covers the end 21 of the filtering material 38 suchthat there cannot be access to the open interior volume 44 at end 54 ofthe filter element 12.

The baffle plate 52 conveys filtered liquid from the filter assembly 10and provides a barrier that prevents the bypass of unfiltered liquidaround the filtering material 38. The baffle plate 52 includes an outer,peripheral edge 56, that forms an outer circumferential wall 58 of thebaffle plate 52. The wall 58 is also the outer radial surface of thebaffle plate 52. The baffle plate 52 also includes axially directedsurfaces 60, 62, which also correspond to a top end surface 64 and abottom end surface 66. The top end surface 64 corresponds to a top face68. The face 68 is generally in a plane that is orthogonal to the outercircumferential wall 58.

The baffle plate 52 includes a hub 70, in particular, a central axiallyextending hub that is interconnected by a plurality of radial webs orribs 72 with a generally circular outer rim 74. The hub 70 defines acentral opening 76, extending through the baffle plate 52 andterminating inside the filter element 12, in particular, inside theinner liner 48. Fluid passages 78 defined by the ribs 72 and thesurrounding hub 70 allow liquid to flow therethrough and into theinterior volume 32 of the filter housing 14.

Threads 80 are provided on the internal surface of the hub 70 forconnecting the filter assembly 10 to the filter head 16 (FIG. 1). Thehub 70 preferably extends below the ribs 72 and into the upper end ofthe filter element 12.

In the embodiment shown in FIG. 2, the filter element 12 is secured tothe baffle plate 52 by direct connection or “potting” of the first endcap 40 to a neck 82 of the hub 70. This method of assembling a filterassembly is described further in commonly assigned U.S. Pat. No.6,345,721, incorporated by reference herein.

Note that the baffle plate 52 has a smooth, continuous, uninterruptedperiphery 56 for its outer wall 58. The outer wall 58 does not have anygrooves (i.e., it is “groove-free”) or any other seats for holdingsealing gaskets therein. Instead, the baffle plate 52 defines a groove84 in the face 68. As can be seen in FIG. 4, the groove 84 is acontinuous circular groove recessed from the top end surface 64 to forma seat 86 for a sealing gasket 88 (FIGS. 2 and 3). In one embodiment,the sealing gasket 88 may be an O-ring gasket. Preferably, the sealinggasket 88 is a lathe-cut gasket 89. The sealing gasket 88 is compressedbetween the baffle plate 52 and the housing 14 to form a seal 92 (FIG.3) therebetween. In FIGS. 2 and 3, it can be seen how the housing 14 isengaged against the baffle plate 52 continuously and uninterrupted alongthe edge 56 and outer wall 58 and then is bent orthogonally thereto toextend over at least a portion of the axial surface 60 of the baffleplate 52. The bent portion 94 of the housing 14 forms seal 92 againstthe gasket 88. The bent portion defines an end tip 108 (FIG. 3). The endtip 108 is spaced from a wall 110 that defines a second groove 96(described below). Lining the groove and extending over it is aplurality of protrusions 87 (FIG. 4). Protrusions 87 help to hold thegasket 88 in place before the seaming operation (bending the housing 14thereover).

By locating the sealing groove 84 in the face 68 of the baffle plate 52instead of along the circumferential edge 56, the gasket 88 is locatedin seat 86 that is cast into the face 68 of the baffle plate 52 insteadof being machined into the perimeter of it (as shown in the prior art,FIG. 6). As a result, machining time is reduced, the porosity that isexposed is negligible, and the step of impregnating with Loctitematerial is eliminated. Further, the gasket 88 is compressed by theseaming operation of bending the housing 14 to form bent portion 94against the axial surface 60 of the baffle plate 52. This eliminates anextra step of compressing the sealing gasket 218 into the groove 216(FIG. 6).

Before connection to the filter head 16, there is another sealing gasketmounted within the baffle plate 52. In particular, the baffle plate 52includes second groove 96 to form a second seat 98 to receive a sealinggasket (not shown) therein. This sealing gasket forms a seal with thefilter head 16.

D. Methods

In operation, the filter assembly 10 works as follows: in a forward-flowoperation, fluid to be cleaned enters the filter head through inlet 22.From there, it flows through the openings 78 in the baffle plate 52 andinto the open interior volume 32 of the filter housing 14. From there,the fluid is forced to flow through the filter media 46 and into theopen interior volume 44. The fluid is prevented from bypassing flowingthrough the filter media 46 due to a seal 102 formed between the filterelement 12 and the neck 82 of the baffle plate 52. The seal 92 betweenthe baffle plate 52 and the housing 14 prevents leakage to the outside.

From the open interior volume 44, the cleaned fluid passes through theflow passage 81, which is defined by the interior of the opening 76 ofthe baffle plate 52. The cleaned fluid then exits the filter assembly 10and flows through the filter head 16 and out through the outlet 24.

After a period of operation, the filter media 46 will become occluded.The occluded filter media 46 will cause an increase in restriction. Atsuch time, it will become appropriate to change and replace the filterassembly. In order to do this, the filter assembly 10 will be releasedfrom the filter head 16 by unscrewing the filter assembly 10 from thefilter head 16. This will release a seal formed between the filter head16 and the second groove 96 of the baffle plate 52. The old filterassembly 10 is discarded and replaced with a new filter assembly 10. Thenew filter assembly 10 is screwed onto the filter head 16 and filteringcan then be restarted.

To assemble the filter assembly 10, the baffle plate 52 is provided. Thefilter element 12 is made by providing the extension of filter media 46,inner liner 48, and potting the two ends of the filter media 46 into thefirst and second end caps 40, 42. Preferably, the first end cap 40 ispositioned against an engagement surface 104 of the hub 70 prior toplacing the filter media 46 into the end cap 40. Adhesive pottingmaterial 106 is placed into the end cap 42, and the filter media 46 ispositioned into the end cap 42. Next, adhesive potting material 106 isplaced into the end cap 40, and the filter media 46 is positioned in theend cap 40. The potting adhesive 106 contacts and bonds to each of theend caps 40, 42, the filter media 46, and the engagement surface 104 ofthe hub 70. Next, the filter housing 14 is placed over the element 12having the baffle plate 52 secured thereto. The housing 14 is seamed orbent over the axial surface 60 to form bent portion 94 and to compressthe gasket 88 between the bent portion 94 and the baffle plate 52 toform seal 92 therebetween.

1. A method for constructing a fluid filter; the method comprising: (a)providing a housing having a closed end and an open end; (b) mounting afilter element and a die cast baffle plate assembly into the housingthrough the open end; (i) the baffle plate including a first axial facewith an exterior top end surface and an outer circumferential wallcircumscribing the first axial face; the first axial face being in aplane orthogonal to the outer circumferential wall; (ii) the outer wallbeing an outer radial surface, groove-free, and without any seats forholding sealing gaskets therein; (iii) the first axial face defining atleast a first sealing groove; (A) the first sealing groove being acontinuous groove extending into the first axial face to form a seat;(B) the first sealing groove being cast into the first axial face; (C) asealing gasket oriented in the seat of the first sealing groove; and (c)bending a portion of the housing against the sealing gasket to form aseal between the housing and the baffle plate.
 2. A method according toclaim 1 wherein: (a) before said step of mounting a filter element and abaffle plate assembly into the housing, orienting the sealing gasketinto the first sealing groove on the first axial face of the baffleplate.
 3. A method according to claim 1 wherein: (a) the housingincludes an outer wall; and (b) the step of bending a portion of thehousing includes bending a portion of the housing to extend orthogonallyto the outer wall of the housing.
 4. A method according to claim 3wherein: (a) the step of bending a portion of the housing to extendorthogonally to the outer wall of the housing includes bending a portionof the housing defining an end tip so that the end tip is spaced from awall in the first axial face.
 5. A method according to claim 1 wherein:(a) the step of mounting a filter element and a die cast baffle plateassembly includes mounting a filter element having a first, closed endcap; a second, open end cap; and an extension of pleated filter mediasecured to the first and second end caps; (i) the extension of pleatedfilter media defining an open filter interior.
 6. A method according toclaim 5 wherein: (a) the step of mounting a filter element and a diecast baffle plate assembly includes mounting a baffle plate having a hubdefining a central opening therethrough; the hub extending through thesecond open end cap and into the open filter interior.
 7. A methodaccording to claim 6 wherein: (a) the step of mounting a filter elementand a die cast baffle plate assembly includes mounting a baffle platehaving a plurality of radial ribs extending from the hub.